Foam Series: Choosing the Best Foam for Cushions — 5 Key Terms to Know

To help you navigate your options, we’ve put together this guide to the most important foam terms. Understanding these concepts will empower you to choose the perfect foam for any indoor or outdoor cushion project.

5 Important Foam Terms to Know

Foam Density: The #1 Indicator of Longevity

Foam density refers to the weight of the foam in pounds per cubic foot. It’s a measure of how much material (vs. air) is packed into the foam. In general, higher density foam lasts longer and offers better support — but more isn’t always better depending on the use case.

Here’s a breakdown:

• Marine cushions: 1.2 – 1.8 lb./ft³ is standard. Great for seasonal or occasional use. Our CushionRite® Standard Antimicrobial Foam fits the bill.
• Everyday indoor seating: Look for 2.5 lb./ft³ or higher. Ideal for high-use applications like sofas or full-time liveaboard boats, like CushionRite® Premium Foam.

IFD (Indentation Force Deflection): Foam Firmness Rating

Indentation Force Deflection (IFD) measures how firm the foam feels. It’s determined by how many pounds of force are needed to compress the foam by 25%. Higher numbers indicate firmer foam.

• Extra Soft: less than 24 lbs. 
• Soft: 25-39 lbs.
• Medium: 40-59 lbs.
• Firm: 60-75 lbs.
• Extra Firm: 76 lbs. or higher

Choose the firmness level based on comfort preference and intended use. Firmer foam is generally better for seating support, while softer foam can work well for backrests or headboards.

Antimicrobial Foam: Ideal for Outdoor Cushions

Antimicrobial foam includes additives that resist mold, mildew and bacteria — a must for foam used in outdoor cushions or damp environments.

Most polyurethane foam does not drain easily, so antimicrobial protection helps extend its lifespan and keeps cushions fresh. Just look for “Antimicrobial” in the product title when shopping.

Reticulated Foam: Best for Water Drainage

You’ll often see the term reticulated used to describe open cell foam with excellent airflow and drainage. This type of foam has its cell walls “blown out,” creating a breathable structure ideal for marine and outdoor settings.

Sailrite’s CushionRite® Dry Fast Antimicrobial Foam is a top choice for patio furniture, cockpit cushions, poolside lounges and boat seating that gets wet. It dries quickly and resists mold growth — perfect for any moisture-prone environment.

Foam Usage: Occasional vs. Frequent Use

At Sailrite, we make it easy to narrow your options by usage type:

• Occasional Use: Weekend boaters, patio cushions and formal living room furniture.
• Frequent Use: Family room sofas, daily-use chairs, or full-time cruiser settees.

Choosing the correct foam grade based on use frequency will help your cushions hold their shape and support for years to come.

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To continue learning more about foam, head over to the next post in our foam series “Comparing Types of Upholstery Foam.”